“It’s right that the Government should now say sorry for the despicable way they were treated.”

Karen Keys

Margaret, 35, was a Glasgow University psychology graduate while 32-year-old Frances had a political economy degree from the same uni.

They inherited a burning sense of social justice from their dad John McPhun, a timber merchant and east end councillor who helped to found the People’s Palace on Glasgow Green.

As members of the militant Women’s Social and Political Union, who used the slogan “deeds, not words”, they and other Scottish activists were among 148 people arrested for smashing shop windows in London in March 1912.

The now defunct Daily Graphic reported at the time: “The West End of London last night was the scene of an unexampled outrage on the part of militant suffragists.

Karen has inherited a collection of suffragette memorabilia from the sisters. They include the medals which were awarded to Margaret and Frances for going on hunger strike and being force-fed behind bars.

She also has a copy of Holloway Jingles, a booklet written by the defiant Glasgow WSPU members while in Holloway.

In it, Margaret dedicates a poem titled To A Fellow Prisoner to her friend Janie Allan, who was also imprisoned.

Karen’s collection includes photos of the sisters plus a series of letters written by the pair during their incarceration.

Miss Billington carries a banner enscribed with the suffragette slogan 'Votes For Women' during a demonstration at Westminster

In a letter to Laura Underwood, WSPU organising secretary in Glasgow, Frances said: “I started a letter to you on the third day of the fast but, when I was in the middle of it, the doctor and nurse and helpers rushed in.

“A sheet was thrown round me, I was held down in a chair and pints of milk were poured down my throat.

“Don’t gasp with horror, it was only the feeding cup they used. I didn’t feel equal to the nasal tube.

“They give you the choice. ‘Will you take the feeding cup or must we force it thro’ the nose?’ they say. I took the cup. I had made up my mind to hunger strike but I wasn’t prepared to risk being forcibly fed thro’ nose.

“Margaret took the cup too – I made her promise to take it.

“Miss (Janie) Allan had a feeding cup too. She made a brave fight – she barricaded her cell and it took three men with iron bars three-quarter hours to break it in!”

In another letter, Frances wrote: “My other cell was warm at least – this one is damp and icy. I couldn’t sleep all night.

“I think the warden must have had instructions to make us as uncomfortable as possible.

“I haven’t had hot water or a bath since I came here a week ago. My hands are frozen, so are my feet.

“It isn’t legal for them to freeze us to death.”

The McPhuns used the surname Campbell when they were jailed in a bid to thwart the authorities by hiding their middle-class status in order to protect working-class prisoners.

Elspeth King, author of The Hidden History Of Glasgow’s Women, said: “They really put themselves on the line and into harm’s way in order to win basic freedoms that we take for granted today.

“The women who gave false names did so in order to prove that working-class women were treated very differently from middle-class ones.

“Ordinary women got brutalised behind bars because they didn’t have the protection of middle-class status.”